Study of Dark Conductivity and Photoconductivity in Dysprosium Doped Zinc Oxide Synthesized by Heat Treatment Method

In present work an attempt has been made to study photoconductivity and dark conductivity in dysprosium doped zinc oxide synthesized by heat treatment method. Voltage dependence of photocurrent and dark current and wavelength dependence of photocurrent have been measured at room temperature under visible illumination. The Variation of photocurrent as well as that of dark current with applied voltage is super linear in nature. Rise and decay curve exhibits anomalous behavior of photocurrent wherein the photocurrent decreases even during steady illumination. Photocurrent is found to be maximum in UV range corresponding to band gap of ZnO. Another peak related to defect is found in visible region around 546 nm. Structural study has been performed using X-ray diffraction (XRD) and SEM. XRD indicates that ZnO is single phase with wurtzite structure. SEM images of ZnO: Dy (0.50 %) indicate formation of spherical shape particles of size of the order of few tens mu m.